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An exchange is not just a transfer, it is a transfer at a price. Sure, you can transfer 1 BTC to 100$, but how do you determine a price? If A wants to buy 1 BTC

An exchange is not just a transfer, it is a transfer at a price. Sure, you can transfer 1 BTC to 100$, but how do you determine a price? If A wants to buy 1 BTC from B, what is the transaction? 1$,5$,1000$? You need to integrate with the fiat system and you need a limit order book. I would suggest Harris book on microstructure for an understanding of exchange markets (ISBN 0195144708).

luisivan 13y ago
Each peer has to determine a price per Bitcoin when opening the order. Then we match the orders that have the same price using a P2P discovery system. So there isn't a global price but rather each user has to choose a price.
- bachback 13y ago
  Well, a chosen price is a limit order, which can go unfilled. If I order 1000 BTC for 0.01$ am I going to get filled? At current market prices no, because currently there is no supply of BTC at that price. A market determines the price. If a good is well defined a market will automatically be centralized. Gold and oil are extremely liquid markets traded on exchanges, that means traded based on limit order books.
  - luisivan 13y ago
    Exactly, that's why we will include some graphs about the state of the market so people can figure out their prices
    - bachback 13y ago
      The NYSE processes millions of orders per second, MtGox hundreds per second. So you have machines which work over a protocol (FIX) to establish the price mechanism. In a exchange system there are limit orders and the limit orderbook. You basically have a timestamp problem, which is kind of prependicular to the bitcoin system. At every point t in time, there is a fair value of BTC-USD. And a system which solves that problem will be highly centralized, by definition. So unless you come up with a new system for processing limit orders, people will be arbitraging between a slower system and MtGox, Bitstamp, etc.
      - luisivan 13y ago
        We know, you cannot get informed of every single trade made because of the P2P architecture. But you can still use the exchange if there are enough trades that you are informed of!
        bachback 13y ago
        What problem you are actually wanting to solve? I don't see why I would use a slower system. waiting can be very costly if the price is moving against you. you need quick traders to provide liquidity. which is what you will find if you get users onto such a system. the high volume traders won't like it. I think there is actually room to reinvent the worldwide exchange system.
clarkm 13y ago
Thanks for the book recommendation. This has been something I've been thinking about for several months now: how would a p2p exchange possibly implement a time-price priority queue to ensure proper order execution? The more I think about it, the more I convince myself that it is likely impossible to get network incentives to line up correctly without relying on a trusted third-party (or making other show-stopping compromises). Nodes have no incentive to rebroadcast orders that conflict with their own, and any sufficiently motivated attacker could place nodes in strategic places in the network to manipulate execution in their favor. If anyone wants to talk about this in detail, shoot me an email.

luisivan 13y ago

Each peer has to determine a price per Bitcoin when opening the order. Then we match the orders that have the same price using a P2P discovery system. So there isn't a global price but rather each user has to choose a price.

bachback 13y ago
Well, a chosen price is a limit order, which can go unfilled. If I order 1000 BTC for 0.01$ am I going to get filled? At current market prices no, because currently there is no supply of BTC at that price. A market determines the price. If a good is well defined a market will automatically be centralized. Gold and oil are extremely liquid markets traded on exchanges, that means traded based on limit order books.
- luisivan 13y ago
  Exactly, that's why we will include some graphs about the state of the market so people can figure out their prices
  - bachback 13y ago
    The NYSE processes millions of orders per second, MtGox hundreds per second. So you have machines which work over a protocol (FIX) to establish the price mechanism. In a exchange system there are limit orders and the limit orderbook. You basically have a timestamp problem, which is kind of prependicular to the bitcoin system. At every point t in time, there is a fair value of BTC-USD. And a system which solves that problem will be highly centralized, by definition. So unless you come up with a new system for processing limit orders, people will be arbitraging between a slower system and MtGox, Bitstamp, etc.
    - luisivan 13y ago
      We know, you cannot get informed of every single trade made because of the P2P architecture. But you can still use the exchange if there are enough trades that you are informed of!
      - bachback 13y ago
        What problem you are actually wanting to solve? I don't see why I would use a slower system. waiting can be very costly if the price is moving against you. you need quick traders to provide liquidity. which is what you will find if you get users onto such a system. the high volume traders won't like it. I think there is actually room to reinvent the worldwide exchange system.

clarkm 13y ago

Thanks for the book recommendation. This has been something I've been thinking about for several months now: how would a p2p exchange possibly implement a time-price priority queue to ensure proper order execution? The more I think about it, the more I convince myself that it is likely impossible to get network incentives to line up correctly without relying on a trusted third-party (or making other show-stopping compromises). Nodes have no incentive to rebroadcast orders that conflict with their own, and any sufficiently motivated attacker could place nodes in strategic places in the network to manipulate execution in their favor. If anyone wants to talk about this in detail, shoot me an email.